How to make conversion between RGB and HSV? [Python sourcecode]

soyizi

I get following codes from a Japanese Ghost's Blog, so I neglect the original URL for my hate of them.


RGB => HSV


def RGB2HSV( r, g, b ):
r, g, b = map( float, (r,g,b ) )
if r == g and g == b:
   ma = r
   mi = r
   h = 0
   v = r
elif r > g and r > b:
   ma = r
   mi = min( g , b )
   h = 60 * ( g - b ) / ( ma - mi ) + 0
elif g > b and g >= r:
   ma = g
   mi = min( b , r )
   h = 60 * ( b - r ) / ( ma - mi ) + 120
elif b >= r and b >= g:
   ma = b
   mi = min( r , g )
   h = 60 * ( r - g ) / ( ma - mi ) + 240
else:
   print "Error."


if ma == 0:
   return 0, 0, 0

s = (ma - mi) / ma
v = ma


return h, s, v




HSV => RGB


def HSV2RGB( h, s, v ):
hi = int(h / 60) % 6
f = h / 60 - hi
p = v * ( 1 - s )
q = v * ( 1 - f * s )
t = v * ( 1 - ( 1 - f ) * s )


if hi == 0:
   r = int(round( v ))
   g = int(round( t ))
   b = int(round( p ))
elif hi == 1:
   r = int(round( q ))
   g = int(round( v ))
   b = int(round( p ))
elif hi == 2:
   r = int(round( p ))
   g = int(round( v ))
   b = int(round( t ))
elif hi == 3:
   r = int(round( p ))
   g = int(round( q ))
   b = int(round( v ))
elif hi == 4:
   r = int(round( t ))
   g = int(round( p ))
   b = int(round( v ))
elif hi == 5:
   r = int(round( v ))
   g = int(round( p ))
   b = int(round( q ))
   
return r, g, b